pleroma_secret config file defined in one place

src/freedombone-app-pleroma

 PLEROMA_ADMIN_PASSWORD=
 PLEROMA_DIR=/etc/pleroma
 PLEROMA_SECRET_KEY=""
+pleroma_secret=$PLEROMA_DIR/config/dev.secret.exs
 
 PLEROMA_BACKGROUND_IMAGE_URL=
 
         echo $"Missing directory $PLEROMA_DIR/config"
         exit 7835393
     fi
-    pleroma_secret=$PLEROMA_DIR/config/dev.secret.exs
     if [ ! -f $PLEROMA_DIR/config/dev.exs ]; then
         echo $"Did not find $PLEROMA_DIR/config/dev.exs"
         exit 78923528
 
     # We need to set up the url option again because it somehow gets
     # lost during mix compile
-    pleroma_secret=$PLEROMA_DIR/config/dev.secret.exs
     if ! grep -q 'watchers: [],' $pleroma_secret; then
         sed -i 's|watchers: \[\]|watchers: \[\],|g' $pleroma_secret
     fi